1. Field of the Invention
This application relates generally to a process of biodegradation of groundwater pollutants.
2. Discussion of Background
Bacterial remediation of soil and groundwater contaminants are well known in the art. Hegeman et al in U.S. Pat. No. 5,024,949, incorporated herein by reference, teaches bacterial isolation, selection, and amplification techniques for providing bacterial cultures useful in the degradation of chlorinated aliphatic hydrocarbons. The teachings of Hegeman et al are applicable to other soil or water borne contaminants where bacteria are known to convert or degrade a contaminant to safe or less harmful metabolic byproducts. It is well known in the art to adopt bacterial selection protocols to identify and culture strains of bacteria with a degradation (metabolite) preference for a single chemical species, such as TCE, even when similar chemical hydrocarbon species are also present.
Heretofore, the use of bacterial agents to remediate groundwater and soil contaminated sites have been largely confined to passing contaminated water and soil through incubation tanks housing cultures of specified bacteria under optimal pH, temperature, and nutrient conditions. This treatment protocol is capital and labor intensive, requires frequent monitoring, and long periods of time.
In situ treatment of groundwater and soil contaminants with bacterial agents is also known. However, in situ treatments typically employ the introduction of controlled levels of nitrogen, phosphorus, air, and other nutrients in an effort to stimulate bioremediation. The introduction of nutrients often generates excessive growth and plugging of access wells and injection points. Further, the bacterial bloom which results is often nonspecific which may dilute the presence and activity of the desired bacterial agent, or promotes bacterial activity which produces unwanted byproducts (such as vinyl chloride) as opposed to a preferred metabolic degradation pathway. In addition, the nutrient supplementation occurs on a rather large scale and is therefore costly.
Accordingly, there is room for improvement and variation in the art of bioremediation processes and treatment protocols.